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help ! - 3 way sound system boxes ideas

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Forum Name: Plan Requests
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URL: https://forum.speakerplans.com/forum_posts.asp?TID=88826
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Topic: help ! - 3 way sound system boxes ideas
Posted By: redgoldandgreen43
Subject: help ! - 3 way sound system boxes ideas
Date Posted: 25 September 2014 at 10:15pm
Hi everyone !

I have thrown up my old boxes and now looking for good plans for a mono stack (1 scoop 1 lowmid 1 mid-top).  I play reggae / dub music on a 3 way Dubsonic preamp (cutoff frequencies 120hz / 4khz).

Ive already got 2 PD 156 and i want to use them again, so i will only have to buy the missing mid and top (probably a fane 12" with compression). 

So, the questions are :

- according to the preamp cutoff frequencies is it better to do 1 scoop 1 lowmid 1 midtop or 1 bass 1 mid 1 top ?
- can i use one pd 156 in a 15" scoop and the other one as lowmid ?
- could i use these 2 boxes (above scoops and under tweeters) for my system ? where can i find their plans ? they are cute !...

 

thanks a lot ! :-)

bless up



Replies:
Posted By: bee
Date Posted: 25 September 2014 at 10:39pm
can you not get your pre modded, to suit the xovers you needs....

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https://www.elements-audio.com


Posted By: redgoldandgreen43
Date Posted: 25 September 2014 at 11:15pm
thx for your reply.
i would prefer avoid modding the pre if possible...  (3 months wait + 150 euros fees for this mod)
i wonder why its so complicated, as these pre's frequencies are very common : barracuda, mostec 3 ways got the same cutoff freq if my memory's good. But what kind of boxes did they traditionnally use with them ? i'm totally lost. i can start building any box, but i want to use these pd 156....
thx again for your help !


Posted By: bee
Date Posted: 25 September 2014 at 11:32pm
the 4k xover point, is aimed at reflex tops, but is still asking a lot of a 12" driver, considering most good 1" comps can play better from 2k than a 12".....
 
the high pass of 120hz is crossing right in the key high bass region. rearly I would run.
 
35hz to 80/90hz sub
80/90 to 160/180 high bass (kick)
160/180 to 1.5k mid
1.5k out hf
 
and use an internal xover in your top box 12" to 1"hf
 


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https://www.elements-audio.com


Posted By: bee
Date Posted: 25 September 2014 at 11:35pm
in your case starting with a new system, your very limited to cab choice on the current xover points.
I would plan the system hf first and work down. making sure each box plays well with the next etc. Then get the xover points changed to suit your system.... and use an internal xover board in your tops... 12" to hf


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https://www.elements-audio.com


Posted By: bee
Date Posted: 25 September 2014 at 11:41pm
why not do
 
2 x 15" scoops
2 x single 15" high bass
2 x 12" and 1" mid tops
 
run 4 way, 3 from your pre and 1 built in on the tops....
getting any scoop to play up to 120hz is already a compromise...
 


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https://www.elements-audio.com


Posted By: redgoldandgreen43
Date Posted: 25 September 2014 at 11:44pm
thanks mate for the frequencies scheme, very good to understand how it works :)
i think you're right, i'm gonna build 2 15" scoops first try, and load them with my PD 156.
i will probably put 4 cheap boxes a relative will give me and see how the scoops work this way, for fun.
then i'll ask for freq. mod as you said. in the meantime i think i'm gonna go back to full range use of my preamp :-/ 


Posted By: Dub Specialist Sound
Date Posted: 25 September 2014 at 11:57pm
Thats why most people just jump in and get a pre-amp, yu should decide the box set up yu want first then have pre-amp builder , build the freqencies yu require...

ie scoops do you want them play as high as 120? you probley need reflex for that, cus that in upper-bass reign


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Musical Roots Reggae Vibration is Life! for music is sound...sound is vibration...vibration is energy... and energy begets life. Therein lies my passion!...MUSIC IS LIFE...


Posted By: bee
Date Posted: 26 September 2014 at 12:02am
no point in scoops playing to 120hz, even 15" scoops will have the scoop frequency dip at around that point.....

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https://www.elements-audio.com


Posted By: Dub Specialist Sound
Date Posted: 26 September 2014 at 12:08am
Exactly Bee , thats what i was getting at, he could send a full range signal to lms, active x/o ect...one option 

is a very wide bandwidth 120hz / 4khz man, as he says the pre is, it needs chopping up


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Musical Roots Reggae Vibration is Life! for music is sound...sound is vibration...vibration is energy... and energy begets life. Therein lies my passion!...MUSIC IS LIFE...


Posted By: bee
Date Posted: 26 September 2014 at 12:18am
defo, this is a common fail, seen a lot of sounds buy the pre then build a system to suit it. In 99% of cases it ends with pre needing modding...
 
I would assign your self to this, and build your system so the cabs compliment each other, then get pre changed....
 
I have a unit that could be the answer to this common issue, but a bit more playing is needed. Its a 4in 4out basic lms with 32 band eq per input, and all inputs are matrix able.  so 2 inputs can be assigned to the same output, used post pre, it over rides and xover points set on pre....


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https://www.elements-audio.com


Posted By: redgoldandgreen43
Date Posted: 26 September 2014 at 11:44am
thanks guys ! 3 things and we have finished :D
- so if i understand you well, the mod for my 3 way preamp should be, cutoff
from 120 / 4khz to 90 / 1.5khz  and final stack will be scoops + lowmid + midtop
in any case, if i understand well, the mod will cost much less than the compromise i could get by going 4 way to cover the full frequencies spectrum ... ?
- why did the well known preamp builders choose these frequencies then ?
i thought they chose them, because people used to play this way.
- ive been given 2 vintage valve amplifiers (KT88) by a friend who went transistor. he told me these were 100 watts amps and that i could use one for my scoops to get a warm bass. is that really better on basses ? (ive already heard valve amp on mid and that was amazing)

thanks again guys !

if you want to trade exchange some vinyl records (roots, digi, etc) just tell me.
im a vinyl collector since like 10 years and perhaps ive got things you are looking for



Posted By: bee
Date Posted: 26 September 2014 at 12:09pm
Choose your new boxes first, then see were best suits them for final xover points, then get pre modded

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https://www.elements-audio.com


Posted By: Dub Specialist Sound
Date Posted: 26 September 2014 at 12:24pm
Defo Bee! Thumbs Up

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Musical Roots Reggae Vibration is Life! for music is sound...sound is vibration...vibration is energy... and energy begets life. Therein lies my passion!...MUSIC IS LIFE...



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